Wireless communication systems, such as radio frequency utilized systems, are advantageous for an emergency communication in that no physical interconnection is required between the transmitter and the receiver; once the information signal is modulated to form a modulated signal, the modulated signal may be transmitted over large distances.
A cellular communication system is one type of wireless communication system. A cell phone operative in such a cellular communication system contains circuitry permitting simultaneous generation and reception of modulated signals. Two-way communication between a radiotelephone and remotely-located transceivers is thereby permitted. A cellular communication system is formed by positioning numerous base stations at spaced-apart locations throughout a geographical area. Each base station contains circuitry transmitting modulated signals to a radio transceiver, thereby permitting communication between two cell phones.
One of the problems associated with cell phones is cell phone batteries can run out completely at the moments of an emergency when one needs call for help from the police or fire departments, or emergency services, and there is no other communicating way available. There is a need for a stand alone emergency signal unit operative in a standard cell phone which is applicable of sending out information for emergency rescue in following situations:
1. An emergency while the cell phone runs out of its regular battery completely; or the regular battery is too depleted to be functional;
2. An emergency in which caller is not capable of communicating vocally; and/or
3. An emergency in an unfamiliar area where a caller does not know his or her location.